zigzag240 Posted July 28, 2007 Share Posted July 28, 2007 I have a '71 240 with L28, 4.11 R200 and '82 5-speed I've been running for years with no problems, autocrosses, fast street, etc. Today I tried a fast launch from idle, and as soon as the clutch was let out I heard a metallic ratcheting sound from under the rear of the center console...exactly like the sound a power drill makes when the adjustable clutch slips...but very loud. That spot is over the front of the differential but this was totally different than the common Z rear-clunk. I only happens at launch...not in any other gear or speed. My possible guesses: front diff flange loose, front diff bearing bad, rear driveshaft u-joint. Maybe even the front diff mount...but in the 27 years I've been driving Z's I've never ever heard this sound. I'll drink lots of beer tonight and worry, and will be going under the car tomorrow. Just wondering if this sound rings a bell for anyone else..... Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted July 28, 2007 Share Posted July 28, 2007 Sounds like the front diff mount went away and the drive shaft u-joint is hitting the parking break mechanism. It makes that ratcheting sound. Quote Link to comment Share on other sites More sharing options...
zigzag240 Posted July 28, 2007 Author Share Posted July 28, 2007 I held my camera under and shot a few images, the driveshaft joint and front diff flange look fine. I suspect it's the front diff mount...couldn't be much else, guess I never heard a truly broken mount before...tomorow will tell. Quote Link to comment Share on other sites More sharing options...
rags Posted July 29, 2007 Share Posted July 29, 2007 Yep, what Dan said. Front dif mount will make you lift off the gas in a hurry when it lets the u joint hit the parking brake. Joe Quote Link to comment Share on other sites More sharing options...
zigzag240 Posted July 29, 2007 Author Share Posted July 29, 2007 You guys hit it right on the head...it was a bad diff mount. Just above the diff I could see the edge of the handbrake mechanism was scored from the bolt flange of the driveshaft where it rubbed it...that was the noise. The mount looked ok, but a screwdriver slipped in and twisted would really distort the rubber. A buddy had a new one and I put it in this afternoon. Solid as a rock now...burns off the line now without a hiccup. So don't always listen for a clunk... Quote Link to comment Share on other sites More sharing options...
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